Physical and Swelling Properties of Spray‐Dried Powders made from Starch and Poly(vinyl alcohol)

The aim of this study was to investigate whether starch and poly(vinyl alcohol) could be compatible in a powder for coating. Free films of a mixture of the polymers were produced by casting and investigated with respect to their mechanical properties and moisture uptake. The moisture uptake was substantially higher when glycerol was added and the glycerol‐containing films had a lower failure stress under tension than the corresponding glycerol‐free films. At glycerol levels of 20 wt% or above, the glycerol content resulted in a high strain to failure. Dry powders with and without glycerol were made from the starch/poly(vinyl alcohol) solutions by spray drying. The powders were investigated by differential scanning calorimetry (DSC), to determine the degree of physical ageing or crystallinity. All powders showed a broad peak indicative of the melting of crystals at 100–150°C in the first scan, but this peak disappeared almost completely after rapid cooling. The glycerol‐free powder showed a small endothermic peak at about 45°C, indicating physical ageing of the powders during storage. Suspensions of the powders in a liquid plasticiser (glycerol or poly(ethylene glycol)) showed a sharp increase in storage modulus at a certain temperature, indicating the onset of swelling. The observed swelling meant that some of the powders are good candidates for plastisol coatings.     

Study of Penetration Depth and Droplet Behavior in the Case of a Gas Jet Impinging on the Surface of Molten Metal using Liquid Ga–In–Sn

To study the penetration depth in the case of a gas jet impinging on the surface of liquid steel, cold model experiments were carried out using a liquid alloy Ga–In–Sn, which had similar physical properties as liquid steel. A HCl solution was used to simulate the top slag. The top phase was found to have appreciable effect on the penetration depth. Comparison of the experimental data with the predictions of the existing models indicated that most the model predictions deviated from the experimental results at higher lance heights and gas flow rates. New model parameter was suggested based on the present experimental data. The observation of the formation and movement of metal droplets generated by the gas jet was also made. The velocity of the droplet was found to be at a level only about 1% of the terminal velocity. This low velocity suggested that the turbulent viscosity played important role and the droplets could have long resident time in the slag.     

Mobile exploration of geotagged photographs

Columbus is a mobile application that lets users explore their surroundings through geotagged photographs, presented to them at the location they were taken. By moving around the physical world, the user unlocks photographs and gets to see and experience them in unison with their location. During two consecutive field trials, we investigated how the application was used and experienced and how photographs and locations are explored together. We found that previous experience with the surroundings people was exploring affected how they experienced the localized content. We report on the system’s design and implementation, the trials as well as resulting insights that can be used by other developers of locative media applications.     

Arsenic removal by native and chemically modified lactic acid bacteria

Arsenic in drinking water is a major health problem globally. Simple, novel methods are needed for its removal from water, especially in rural areas. For this purpose, the potential of different microbes in toxin and heavy metal removal from water has gained interest. This study focused on the arsenic removal capacity of three Lactobacillus strains in their native and chemically modified forms. Both native and methylated forms of all three strains were not efficient in arsenic removal. Aminated Lactobacillus casei DSM20011 was observed to remove As(V) but not As(III) in water. Removal was fast, dependent on pH and As(V) concentration. The highest removal percentage 38.1+/-9.0% was observed at the lowest As(V) concentration (100 microg/l) studied at pH 7. The maximum As(V) removal capacity, calculated from Langmuir isotherm, was 312+/-68 microg As(V)/g dry biomass. Interactions between As(V) and the bacteria were weak, demonstrated by release of removed As(V) when contact time was prolonged. Desorption with 1.5 mM HNO3 and NaOH released all bound As(V) indicating that removal occurred at the bacterial surface.     

The Effect of Solid Particles on Liquid Viscosity

The viscosities of solid‐liquid mixtures were experimentally determined for silicon oil‐paraffin system at room temperature and solid‐liquid oxide mixture at steelmaking temperature. The use of oil‐paraffin systems was to confirm the results of high temperature measurements, the experimental conditions being very difficult to control. The silicon oil‐ paraffin mixtures behaved Newtonian until the particle fraction reached 0.15. At this fraction, the mixture started deviate from Newtonian flow; though some average values could still be collected with very high uncertainty. Liquid‐2CaO.SiO₂ mixtures and liquid‐MgO mixtures were studied at steelmaking temperature with carefully prepared particle fractions and well controlled conditions. Liquid‐2CaO.SiO₂ mixture behaved Newtonian even when the particle fraction reached 0.1. The results of both room temperature measurements and steelmaking temperature measurements were used to examine the applicability of the existing models. Einstein‐Roscoe equation was found to be the only model applicably for the systems studied. No modification of the model parameter was found necessary, though the particles were not spherical.     

Towards a shift in mindset: partnering projects as engagement platforms

The last decade has seen shifts in both practice and research regarding client–supplier relationships. Cooperative project client–supplier relationships have become increasingly common, and have spurred a stream of vivid research on for example alliances and partnering. Despite increased attention, an insufficient understanding of the relationship dimension is identified, described as a ‘black box’. Here it is suggested that a key to unlock this ‘black box’ is to focus on the everyday practice and the role of the mindset of involved actors throughout the project. We argue that running partnering projects involves more deeply rooted changes than previously recognized. Changes relate to the mindset among involved actors, where service (instead of merely products or production) becomes the core denominator. First we aim to illustrate that a partnering project, if well functioning, can be understood as an engagement platform, and second we aim to discuss the consequences if this is acknowledged in practice. The case, a successful Swedish partnering project, is explored from a service-dominant logic perspective and it is suggested that successful partnering projects are to be defined as engagement platforms. A refined categorization of the components of partnering is provided and the implications of a shift in mindset discussed.     

Sensor placement for fault isolation in linear differential-algebraic systems

An algorithm is proposed for computing which sensor additions make a diagnosis requirement specification regarding fault detectability and isolability attainable for a given linear differential-algebraic model. Restrictions on possible sensor locations can be given, and if the diagnosis specification is not attainable with any available sensor addition, the algorithm provides the solutions that maximize specification fulfillment. Previous approaches with similar objectives have been based on the model structure only. Since the proposed algorithm utilizes the analytical expressions, it can handle models where structural approaches fail.     

External power frequency magnetic field-induced jitter on computer monitors

Power frequency magnetic fields with flux densities greater than 0.5 μT are not uncommon in offices. This level has been shown to induce jitter on VDT monitors. In the present project, these magnetic field-induced disturbances have been studied in the laboratory in order to establish a firm technical basis for future studies of the disturbance's influence on eye strain in VDT workers. Eight volunteers judged the occurrence of distortion when an applied external magnetic field was varied both in amplitude and frequency for 8 investigated VDT screens. The level of the external 50 Hz magnetic field when the distortion was detectable ranged from 0.6 to 1.1 μT. If the screen was viewed through a stereomicroscope (25 × magnification), the corresponding level was in the order of 0.2 μT. If the frequency difference between the external magnetic field and the refresh rate of the screen is only ±1-2 Hz, the disturbance is noticeable at even lower flux densities.